


An Out of Body Experience

by onward_came_the_meteors



Series: Brucemas 2020 [1]
Category: The Avengers (Marvel Movies)
Genre: Avengers Tower, Bodyswap, Bruce Banner Needs a Hug, Friendship, Getting Together, Humor, M/M, Nightmares, POV Third Person, Post-Avengers (2012), Team Dynamics, They can give each other a hug, Tony Stark Needs a Hug, and then a little more than friendship
Language: English
Status: Completed
Published: 2020-12-14
Updated: 2020-12-14
Packaged: 2021-03-11 02:47:21
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 12,890
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28068009
Author URL: https://archiveofourown.org/users/onward_came_the_meteors/pseuds/onward_came_the_meteors
Summary: Tony continued. “‘Cause, you know, there’s already that whole ‘two heads are better than one’ thing. So if we’ve got two heads, but one head is actually the other head, and that head is really the first head, and both heads get to share heads with the other heads—”“Please,” Bruce said. “Stop talking.”Or, Bruce and Tony switch bodies. And realize some feelings.
Relationships: Bruce Banner/Tony Stark
Series: Brucemas 2020 [1]
Series URL: https://archiveofourown.org/series/2056074
Comments: 10
Kudos: 78
Collections: Brucemas 2020





	An Out of Body Experience

**Author's Note:**

> So... this was not meant to be this long, but what can I say, I love the science bros :D
> 
> Day 1, for the Tony/Bruce pairing and the prompt "glasses."

Their latest mission had lasted seven consecutive hours, and so the only reactions when the quinjet finally came to a rest on the landing pad were assorted groans, mumbles, and Tony’s half-hearted “home sweet home” from the pilot seat. Bruce was pretty sure JARVIS was overriding the controls that held the doors open to give all of them more time to stagger out and onto the roof of the tower.

At least Bruce wasn’t the only one coming back exhausted this time.

He wrapped the sleeves of his borrowed hoodie tighter around himself and followed the rest of the team out of the jet, blinking at the sudden onslaught of sunlight into his eyes. His surroundings still held that familiar fuzzy quality that lingered after every transformation as his perception adjusted and shrunk to fit. His eyelids were a heavy weight every time he lifted them open, and the bed in his room of the tower—the couch was also a strong contender—sounded like the best thing in the world.

Unfortunately, Steve had stopped just outside the roof door, his brow furrowed and his hand brushing the coms in his ear as though listening to something. 

“Hang on, guys,” he said, gesturing to the others—particularly Natasha, who had already opened the door a crack—to stay where they were, and Bruce’s hopes sank.

“S.H.I.E.L.D.?” Clint asked, appearing somewhere behind Bruce’s shoulder and nearly making him bump into Thor. The archer didn’t look at all apologetic, however—actually, Bruce wasn’t positive he’d seen Clint make a facial expression in the past hour or so. 

Steve nodded.

On his other side, Tony lowered his faceplate, revealing a sheen of sweat and a few lightening bruises where his forehead had banged into the inside of the helmet. “Don’t suppose they’re calling to congratulate us on a job well done,” he mused. “Now that would be a nice change of pace.”

“And possibly a sign that S.H.I.E.L.D. had been infiltrated,” Natasha offered. She was leaning a little on Clint’s shoulder, and Bruce worried for a moment that she was injured, but she was just fixing one of her boots. Her only visible wound was a cut above her eye that had been stitched up on the flight back, but that didn’t mean much.

“See, this is why we keep you around. The incessant optimism.”

Natasha smirked, but Steve was talking again before she could reply.

“Got it. We’ll be there.” Steve twisted the coms out of his ears and slipped them into one of the many intriguingly-purposed pockets on his utility belt before facing the rest of them. “Don’t shoot the messenger, but we’ve all got debriefs today on account of the ‘sensitive nature’ of the mission.”

“That’s one way of putting it,” Clint said under his breath, wincing as he bent a sore arm back to unhook his quiver. “They say when?”

“They’re giving us a few hours to recover.” From the slight inflection Steve placed on that last word, it was clear what he thought of S.H.I.E.L.D.’s idea of a timeframe. “So I’d suggest you all shower quickly.”

“I don’t know why I always have to go to these things,” Bruce remarked. “All I can tell them is whether the pile of rubble I wake up in is cement or concrete.”

Steve and Natasha answered almost at the same moment:

“Team morale.”

“Insurance reasons.”

Bruce glanced between them. “Good to know I’m appreciated.”

The door opened and the team began to file inside. Inside was nice: inside was arc-reactor-generated air conditioning and floors that weren’t strewn with shards of glass and wreckage and JARVIS’s familiar greeting that everyone was too tired to do much more than nod at. Definitely an improvement.

Bruce leaned more heavily than usual on the railing as he made his way down the stairs, going slowly in part because his body was not pleased at being turned inside out and flung into a battle and in part because if he went any faster, he would probably walk into Clint.

Once they’d all reached the common area, Tony started taking off the rest of his suit, shedding bits of metal the way another man might unbutton his coat and drape it over the couch. All the while, he maintained the silent argument he’d been having with Thor almost since they’d landed, which was a pretty impressive display of multitasking if nothing else.

What this argument constituted, Bruce didn’t know, but it seemed to involve… some small object that Tony and Thor seemed to be playing an odd game of keep-away with. As of current, Thor had it tucked between his arm and his side, standing as solidly as a brick wall and ignoring Tony’s exploring arm trying to steal the object back. Bruce couldn’t see what it was, but he vaguely remembered Tony making a joke on the quinjet about “spoils of war.”

_ Whatever it is, I’m sure S.H.I.E.L.D. will want to look at it. And quite possibly confiscate it, depending on what it is, but anything that can hold the interest of both the god of thunder and Tony Stark for that long is  _ definitely  _ the kind of thing that S.H.I.E.L.D. would want to stick a “property” sticker on. _

Which was probably why Tony and Thor were both trying to claim it now.

Bruce braced himself against the nearest wall and tried very hard not to fall asleep against it. These extra few hours in between mission and debrief were almost worse than going straight to debrief; at least then he wouldn’t have to force himself awake during the interim. It was a little better than it used to be, sure, but being the Hulk always took a lot out of him, and Bruce knew that once he fell asleep, he would not be waking up for the foreseeable future.

(These were the times that Bruce wished he could negotiate the whole sharing-the-body thing: not only did the Hulk steal so much of his time while transformed, but the aftereffects lasted for days even once he was back as puny Banner)

That was particularly true for this mission, which had started as an innocent observation-with-the-vibranium-shields-and-magic-hammers-on-standby operation but had quickly turned into an hours-long, crossing-multiple-state-lines catastrophe that had included, among other things, Tony’s near decapitation (while still in the suit, which was a sight that would probably haunt Bruce in his nightmares), Natasha and Thor getting trapped in a sewer and coming out drenched in several undiscovered species of bacteria, Clint crashing a stolen mail truck into the side of the quinjet (he claimed he’d forgotten about the cloaking tech), and Steve almost stopping, dropping, and rolling off a bridge.

In the end (and after far more time than Bruce had ever wanted to spend neutralizing flesh-eating chemicals that had been sprayed onto the skin of his thunder god teammate) they’d emerged victorious. In the most defeated way a victorious group of superheroes could possibly emerge. They’d tracked down the source of the chaos, which had turned out to be a rogue Asgardian ei… ein… a rogue Asgardian  _ something _ , who’d been hiding out on Earth for the past few centuries and apparently decided that now was the right time to let loose.

Seriously, why did these types of beings always pick  _ Earth _ ?

Bruce would’ve expected Thor to be the most helpful one in this situation, but it had ended up being Tony who’d finally clocked the guy on the head with a couple hundred pounds of force and called it a day. That had been as much as Natasha had told him on the flight back, but Bruce could figure out the rest: he’d transformed back, quite possibly passed out, and the rest of the team had boarded the jet with whatever pieces of Asgardian magic-tech they’d managed to recover from the scene. They’d learned the hard way after New York that it was better to clean up after themselves when aliens were in the mix.

Bruce realized his eyes had been slowly sliding their way closed and stood up straighter, taking a step away from the wall and looking around the room. 

Clint and Natasha had already disappeared, and Steve stared at the ceiling for a long moment before he gave himself a little shake and started toward the elevator. He called something over his shoulder that sounded like “remember we’re leaving again in a few hours” before stumbling inside. Bruce was going to be very impressed if Steve actually made it to his floor without falling asleep standing up.

As for Tony, he was completely out of the armor now and had managed to steal the mystery object back from Thor, spinning it around in one hand as he headed out of the room. The lengths to which he pretended not to notice Thor following him were slightly ruined by the fact that he had to speedwalk in order to keep ahead of Thor’s longer legs. 

Bruce was left with the choice of either following them or spending the time before the debrief by himself. Normally, he would take this opportunity to go shower or eat, but right now he desperately needed to be distracted if he was going to make it through the next few hours. 

And whatever else you could say about Tony and Thor, they were definitely the right people to go to for a distraction.

Bruce could probably get away with showing up as-is to S.H.I.E.L.D. anyway; the Hulk hadn’t rampaged through any mud puddles or piles of dusty debris or (ew) pools of alien guts and plasma this time. As had happened on previous occasions that he didn’t really want to think about while his stomach was still making up its mind on whether it was going to keep his breakfast down. Sure, his hair probably looked atrocious, and he was wearing a hoodie that was oh so definitely Steve’s—even though it had shrunk in the wash, it was still too big for him—but he was way too tired to do anything about any of that.

So he followed Tony and Thor to the lab.

The first thing he saw when he stepped through the door was Tony gesturing at something on the table with his free hand, the other hand busily tapping across a holographic screen in a pattern so familiar Tony only had to glance at it a few times. As soon as he finished with that screen, another flashed up to take its place, and he adjusted seamlessly even as he kept his main focus on his conversation (Bruce would call it what it was: bickering) with Thor.

A smile tugged at Bruce’s face as he watched, and he walked over until he was hovering by a nearby desk.

Tony looked up, grinning when he spotted Bruce. “There you are, Banner, we were waiting for you. Now can you please explain to Sparky over here that this is very sensitive equipment and lightning should not be anywhere near it?”

Thor cut over him almost before Tony had finished speaking. His arms were crossed over his chest, but his expression was more mischievous than annoyed. “Bruce, can you please explain to Stark over here that I have more experience with this kind of magic than he does?”

“Please, it’s always about the magic with you; has no one explained, I don’t know, the laws of physics?” 

Bruce raised his eyebrows. “Tony, are you seriously trying to argue that you know more about Asgardian tech than the Asgardian?” He scooted a swivel chair out of the way so he could get a better look at the object on the table that his teammates—and all the scanning equipment Tony no doubt had running—were so fascinated by. 

It was smaller than he’d expected, the design more reminiscent of Thor’s hammer (and Loki’s scepter) than most of the Chitauri tech they’d picked up after New York. It emitted a faint hum, but didn’t seem intent on doing anything more menacing than glowing a dark gold color. 

Thor laughed. “Excellent point, Banner; much appreciated.”

Tony stuck out his tongue at Thor before addressing Bruce. “Can you really blame me? If the question is ‘does Tony Stark know more about X than X person,’ the answer is almost always yes.’” He grinned as Bruce shook his head.

“Wow, they weren’t kidding about your ego, huh?”

“C’mon, you lo—you like it.”

The object on the table suddenly became a great deal more interesting.

Bruce experimented with how many times he could spin the swivel chair next to him without it squeaking before Tony finally changed the subject.

“So, Thor, if you’re the expert here, why don’t you tell me what this little doohickey can do?” He made a motion as though to poke the object, but evidently decided against it. 

Thor tilted his head. “Well, I believe it to be some kind of m—” he started, before Tony interrupted.

“I should add that if you call it magic I will throw a screwdriver at you.”

Thor grinned. “—magic—” he ducked the screwdriver easily and continued “—meant for capturing energies.”

“And amplifying them for weaponry?” Bruce asked.

Thor shook his head. “More like as a form of transport between one vessel and another. My mother used a similar technique the time Loki switched my mind and body with those of a frog.” He must’ve seen the matching looks on Bruce’s and Tony’s faces, because he hastily added, “This was several centuries ago. And clearly temporary.” He shrugged. “The hardest part was honestly tracking down the frog—”

“—and how about we leave that there?” Bruce broke in. He smiled at Tony’s emphatic nod. “Maybe get some readings on this here before we—” 

He stopped. “Tony. Thor.”

Tony was the first one to respond. “Yeah?”

“Was that…  _ glowing _ so much before?”

Tony’s eyes slid from Bruce’s down to the object on the table. Which was now glowing quite a lot and starting to shake, the strange humming sound growing louder by the second.

_ Shit. _

All three of them moved at the same moment—Bruce going for the button that would lock down the entire lab, Tony reaching for a metal glove, Thor backing up to grab Mjolnir—but they weren’t fast enough. 

There was a deafening blast, and everything swam before Bruce’s eyes. Something seemed to move through him, like the explosion had turned incorporeal, and sparks of pain lit up the inside of his head as the world floated off into a cloud. If he had to pick a color to describe the sensation, it would be light blue. He wasn’t exactly sure why.

And then he was on the floor, and reality came rushing back. 

His fists had clenched involuntarily at some point, and he forced them to relax now, fingers brushing against the cool tile. It didn’t help; his skin was prickling and his head was pounding and the throwing-up feeling that  _ had _ been retreating a bit was now back in full force. 

And just…  _ ow.  _

He pushed himself up until he was braced on his palms and frowned. Something was off.

True, everything was still disoriented, and his blinking to try and clear the gray spots out of his vision was nothing new, but his body somehow felt sore in different places than it had before. Like instead of being ripped open from the inside out, he’d been violently and repeatedly thrown against something very solid and heavy for an extended period of time. He didn’t think the explosion would have affected him  _ that _ much.

His breathing felt odd, too. Shallower, quicker. That wasn’t good. That was never good, but surprisingly, the Hulk didn’t seem to be stirring in the back of his mind. In fact, when Bruce reached out, there was… nothing.

Nothing.

_ That’s… concerning. _

He was kind of surprised at this reaction, to be honest—hadn’t he always wanted the Hulk to leave him alone for once?—but in this case, it was more the sudden drop in his stomach as he realized that he had  _ no idea _ what was going on with his brain-roommate, and he was used to that feeling being ever-present. 

He blinked again and rubbed a hand over his face, only to be met with more oddness. His face felt a different shape than it had moments ago: different in the length, the nose, the structure of the bones… and when he brushed his hand lower, he felt the roughness of facial hair.

Now, Bruce knew he hadn’t been unconscious for  _ that _ long. 

He sat up fully, blinking furiously around the destroyed lab, and—

—found himself staring into his own shocked face.

“What the  _ hell _ ,” he said, and it was settled once he heard his voice—more clipped, less rounded out, with an entirely different lilt—he wasn’t himself. He was…

… and he really didn’t want to finish that thought, but he didn’t really have a choice as the Not-Him a few feet away braced both hands against the floor and muttered, “Am I high?”

“Nope. Unfortunately for both of us.” Bruce was honestly amazed that he could even form coherent sentences, because part of him (a very large part of him that he was seriously considering giving in to) wanted to cover his eyes and scream as loud as he could, because this could  _ not _ be happening. 

But all the evidence was pointed one way. Bruce was in Tony Stark’s body, and Tony… he was in Bruce’s.

Tony tore his gaze away from his hands on the floor and looked up at Bruce again, holding eye contact for a second before a strangled noise escaped his mouth and he started laughing. And didn’t stop.

Bruce didn’t know the last time  _ that _ expression had been on his face and shifted so that he was sitting up with one hand draped over his knee, watching Tony get it out of his system. Or possibly have a mental breakdown. Bruce wouldn’t blame him either way.

Footsteps came from the other side of the room and Thor with them, walking up with Mjolnir in hand and looking (highly unfairly) unscathed.

“Are you two all right?” Thor asked. His gaze darted between Bruce and Tony, a faint furrow appearing between his brows.

The words sent Tony into another bout of laughter, which was starting to get so breathless it sounded more like giggles.

Thor turned to Bruce in confusion. “Did we… break Banner?”

The only answer Bruce could give at first was “Mm,” but he forced himself to stand up and act like a human. Because he was now, in every sense of the word. Including legally. 

“Thor… that isn’t Bruce.”

Thor stared at him. 

“I’m Bruce.”

Thor continued to stare at him. Bruce waited for the moment when he would alert the rest of the team that their resident geniuses had finally crossed the line into mad scientists, when Thor took a step closer and stared hard into Bruce’s eyes. Bruce held as still as he could, and whatever Thor was looking for, he apparently found it, stepping back again with a nod.

Thor looked over at Tony—who was still on the floor, but at least his laughter seemed to be tapering off—and leaned down, offering a hand. “Stark?”

Tony stopped abruptly and glanced down at himself again, as though to double-check that he was still Bruce. 

Thor must have noticed, because the next words out of his mouth were, “Don’t worry, I know who you are. Regardless of the, ah, container.”

“Is my sparkling personality just that self-evident?” Tony raised his eyebrows, but the familiar expression didn’t have quite the same flair when he was using Bruce’s face.

“More like the fact that I’ve never seen you—” Thor pointed to Bruce, still talking to Tony “—be silent for more than four seconds at a time.”

Tony lifted his head. “Hey, rude.” He pointedly stood up without taking Thor’s offered hand, but ended up almost falling into the table—which had been knocked onto its side—and had to catch himself.

“You okay?” Bruce asked. 

“Oh yeah.” Tony gave the side of the table a little pat before letting go. “This kinda thing happens every day, doesn’t it? Just playing Freaky Friday with your best friend.”

Bruce involuntarily inhaled at that last part, the motion pulling on his chest in a way he wasn’t used to. He wondered what kind of scars the arc reactor had left behind even after the surgery—Tony certainly hadn’t ever mentioned any pain, but that meant exactly zip when it came to Tony “forgot-to-mention-when-he-was-actively-dying” Stark. 

At a loss for anything else to say, Bruce settled for, “Well, hopefully this is temporary.” He looked at Thor. “Please? Please say this is temporary?”

Thor nodded. “It’s temporary.” Both Bruce and Tony heaved identical sighs of relief. “But—”

Tony held up his hands. “Hold on there, I liked that sentence the way it was.”

“ _ But _ I don’t know how long it will take for you two to return to your original forms,” Thor continued, ignoring Tony. “I’m not sure what kind of reaction a Midgar—er, human body would even have to this type of power.”

“Yeah, funnily enough, allergies to Asgardian magic didn’t make it to the S.H.I.E.L.D. medical checkup,” Tony said.

Thor frowned at the air like he was calculating something. “Best case scenario, it will be perhaps a day.”

“And worst case scenario?” Bruce asked. Thor paused.

“Um. How long are human lifespans again?”

There was a thud as Tony’s head dropped onto the lab table, and Bruce scrubbed a hand over his eyes. All of his previous exhaustion seemed to have merged with Tony’s exhaustion and multiplied itself. And with the mission they’d both been through earlier, that wasn’t a small—

He froze. There were rustling sounds as both Tony and Thor turned their heads, and both of them were watching him when Bruce opened his eyes.

“Guys,” he said. “We have a S.H.I.E.L.D. debrief in two hours.”

So that was what his “oh shit” face looked like.

* * *

They somehow made it through the quinjet ride back to S.H.I.E.L.D. without raising any suspicion. This was primarily achieved through neither Bruce or Tony saying a single word for the entire flight. How “Tony” not talking for that long didn’t send up any red flags was beyond Bruce, but given that the rest of the team still looked exhausted from the fight earlier—it was safe to say that their one-hundred-and-fifty-four minute break had done fuck-all for their general R&R—they probably weren’t paying as much attention to their surroundings as they normally would. In fact, Bruce was about eighty-five percent sure that Natasha had been using the flight as a chance to take a nap, but he couldn’t see her face in the shadows.

Once the jet landed, they walked into the S.H.I.E.L.D. base, following Steve’s lead. There wasn’t any real reason why it was Steve’s lead they were following—he’d never been to this specific base before—but they were working on autopilot.

The base wasn’t much different from any other S.H.I.E.L.D.-related place Bruce had ever been to, in that it was large, monochromatic, and full of people who didn’t like him. The only difference was that now those people were directing those same suspicious looks at  _ Tony _ . It was actually pretty funny to see Tony’s surprised-then-puzzled-then-glancing-at-Bruce-to-confirm-that-this-was-happening reaction, because sure Tony was used to being disliked for reasons that involved weapons manufacturing, family history, self-professed playboy-ing, or just general personality, but he’d never had anyone reaching for their holsters when he walked in a room. 

Tony had changed into one of Bruce’s shirts before they’d left, which at least didn’t make him look homeless, but it made Bruce even more hyperaware of the fact that  _ that was his body walking around without him in it and this is so wrong on so many levels— _

And the fact that it was  _ Tony _ —

_ Nope. Stop that. Focus. You are Tony Stark now, at least for the next forty-five minutes. _

_ Fuck. _

They made it into the debriefing room, where Fury was waiting for them, looking impatient below the eye patch even though the Avengers were technically on time. 

“Director,” Steve said as a greeting, and Fury nodded, exchanging a look with Natasha as the team slid out chairs from the wide conference table and did their best not to collapse into them.

Bruce automatically went for the chair at the back, but at a much-less-subtle-than-he’d-like look from Tony, he changed course and selected the one on Thor’s left. Which put him right next to Steve. Wonderful.

Tony sat down between Clint and Natasha, which was practically more worrying—even though Clint almost definitely did not have his hearing aids in and was staring blankly at the ceiling, Natasha would be able to spot anything amiss in no time flat. Bruce just had to hope that Tony could sit still, keep his mouth shut, and not draw attention to himself for the entire debriefing.

Yeah, they were doomed. 

Fury started talking, and Bruce tried to listen, but about forty seconds in he convinced himself that not paying attention during a debrief would be a Tony Stark thing to do, wouldn’t it, so it was really very smart of him to just… zone out for a few… 

“Stark?”

_ Oh shit.  _

Bruce blinked, only to find Fury giving him a look. Not a fun experience at the best of times, even worse now that he was trying to keep a cover from someone who was essentially, as Tony had once put it, “the” spy.

Not to mention Steve’s exasperated arm-crossing from beside him, Clint moving his sharp-eyed gaze from the pattern of the ceiling tiles to Bruce’s face, Thor’s wide eyes of wanting to help but being unsure how, and, most unsettlingly of all, Natasha’s scrutinizing look from across the table, 

“I just said that parts of the Iron Legion got tangled on their way to the cleanup site and caused a two-hour bottleneck. You don’t have a comment?”

Bruce’s brain went blank with panic for a moment before he caught Tony’s eyes across the table. Tony’s jaw was tight and his hands were folded on top of each other, but when he met Bruce’s gaze, everything seemed to settle.

_ Okay. I can do this. _

Bruce leaned back in his chair, almost tipping the legs off the floor, and looked up at Fury. “Honestly, Nick, that just sounds like Manhattan traffic.”

There was a brief moment when he wasn’t sure if that would stick, but fortunately, he could always count on Steve to—

“Tony, is this really the time?”

—do exactly that.

As soon as Steve spoke, Fury’s expression shifted to resigned, and Bruce breathed a silent sigh of relief. 

“Don’t worry, I’m already on it.” Bruce slipped Tony’s phone out of his pocket—it unlocked by reading his fingerprint, because of course that had transferred over—and began to tap on the screen. He probably could’ve actually figured out how to send orders to the Iron Legion, given a few minutes, but while he was in a room with some of the most paranoid people on the planet, he didn’t want to risk messing around. Hopefully, the pizza wouldn’t get cold by the time they returned to the tower. “There. Is there anything else you wanted to talk about, or was that it, because I for one feel like that could’ve been an email—”

“Thor,” Fury said, cutting across him.“We need a confirmation on whether the thunderstorm at about two-thirty was caused by regular weather or you directly.”

Thor tried and failed to hide his grin as he’d been watching Bruce, shifting uncomfortably in his seat as he moved his gaze to the director. “Uh, two-thirty, you said? Nope. Not me.” He glanced again—probably inadvertently—between Bruce and Tony, and Bruce felt a bit of nervousness rise again as both Natasha and Fury narrowed their eyes. 

Fortunately, Fury moved on from there to questioning Clint about some failure to answer his coms during the mission (which was half-hearted at best; Bruce had only known Clint for a few months and even he knew that kind of thing was par for the course) and Bruce was able to look over at Tony again. 

Tony’s eyes met his almost immediately, and it was there that Bruce saw the spark of surprise mixed with something like… nope. Nope, not gonna analyze that. Not right now, when he had to be Tony Stark—not a complete mess.

Bruce managed to keep up his Tony impression for the rest of the meeting, drawing on every quip, snark, fidget, and nervous habit he’d ever seen his teammate enact. Fortunately, their IQs had always rivaled each other, and Bruce could technobabble with the best of them, even if he’d have an easier time tracking radiation signals than designing an Iron Man suit from scratch. Whenever he was lost for words, he had the fallback of throwing out a teasing remark at Steve and letting him rise to the bait.

(He wasn’t sure whether or not to be offended that Tony’s impression of him was essentially to sit there like a rock, but he was already nervous enough when it was him talking)

The most surprising part about all of this was that it  _ worked. _

Eventually, once the actual debriefing was done (and at least that part was all electronic, because Bruce wasn’t sure he’d be as good at faking Tony’s handwriting), Fury kicked them all out and the Avengers trooped back to the quinjet. Bruce didn’t miss the covert grin Tony shot him on their way out of the base.

His feeling of triumph evaporated immediately when Natasha quite literally pulled him and Tony aside the minute the jet door closed.

“All right, what’s going on?” Natasha’s arms were crossed, and she was pinning both of them against the row of seats with her critical eye. “You two are acting even weirder than usual, and now you’re pulling Thor into it.” She pointed behind her to indicate the thunder god in question, and Thor looked up from where he’d been having a quiet discussion with Clint, both of them hovering around the pilot seat in a way that made Bruce suspect their discussion was about which of them got to occupy said pilot seat for the flight back.

Tony shrugged. “Hey, he’s a freaking Norse legend who wields a lightning hammer and is obsessed with baking shows; he was already weird.”

Bruce elbowed him. “That is so not the argument we should be having right now—”

“I misdirect when I’m nervous, you should know that by now—”

“Trust me, you don’t need to be worried about running out of arguments we could be having—”

“Yeah, but they’re all going to be on  _ topic _ , because that’s what you  _ do _ —”

“Of all the things—” Bruce stopped abruptly when he saw Natasha smirking in front of them, and Tony’s retort died before he could open his mouth.

The quinjet had gotten very quiet in the last few minutes.

Steve and Clint were both staring, stark confusion evident on both of their faces. Thor made a motion as though to shift in front of them and block the view, but it was a little late for that. 

There was silence, and then Natasha spoke. “Told you they were acting weird.”

Bruce and Tony took a step away from each other, glancing back and forth in a silent  _ you _ , no _ you _ , no  _ you _ that lasted until Bruce sighed and faced the rest of the team.

“Okay,” he said. “Maybe we weren’t as honest as we could have been.”

* * *

Explaining the situation to the team had resulted in mixed reactions.

Clint had started laughing so hard he’d actually fallen over, clutching onto the back of the nearest seat for support and staying there for the rest of the flight. Even after his laughter had abated, a grin snuck back out every time he looked over at Bruce and Tony. Steve hadn’t said a word at first, looking like they’d shoved him facefirst into a brick wall, and had finally just muttered something about “getting that fixed'' and retreated to the back of the jet, pulling out his phone to do something that Bruce hoped was playing Tetris but that could just as easily have been accepting that S.H.I.E.L.D. assignment in eastern Ukraine. As for Natasha, she’d grilled them both with a questionnaire: asking Bruce to remember the details of some sophomore year prank at MIT and asking Tony a question in Brazilian Portuguese. Neither of them could answer, which was apparently good enough for her. 

They didn’t usually eat dinner together, all six of them, but ever since shawarma, it had become a sort of tradition to do after a more intense fight. It gave them company, a safe haven from becoming stuck inside their own heads and vanishing up to the roof or hiding out in their bedrooms or wandering around the city in the dark or forgoing sleep in favor of designing a sentient robotic umbrella—all of which were purely hypothetical situations, of course. 

Also, they were all too exhausted to cook separately. 

Bruce was staring into his plate, moving his fork mechanically up and down and trying to focus on anything except the fact that Tony was sitting across the table wearing his body like a set of clothing. This incidentally led to a lot of thinking about how much he wanted to go to sleep right now—which wasn’t good either. He couldn’t win. 

He wasn’t sure whether anyone else had been talking—he hadn’t been paying much attention and probably wouldn’t have noticed if Steve had climbed on the table and recited the national anthem—but he looked up when he heard his name.

Natasha was two seats away from him, smiling slightly when she saw Bruce lift his head. “So, Bruce,” she repeated. “Out of your two shapeshifting experiences, which one would you say is worse?”

Next to her, Steve choked on his drink, and Clint reached over to pat him on the back.

Bruce grinned. “You really want me to answer that?” 

The look on Tony’s face (which of course was really his face, which was— _ gah, stop  _ thinking  _ about that _ ) was priceless. “Oh, screw you, Banner.”

“I can see where you’re coming from with that,” Thor mused. He reached for a salt shaker and idly began to sprinkle it. “On the one hand, the uncontrollable might of sheer powerful rage.” He looked oddly intrigued by the idea—or maybe not so oddly, considering that this was Thor, who came from a planet where people gave lightning hammers to their toddlers. “On the other hand, Stark.” He gestured to illustrate his point, earning himself a matching glare from Tony.

“Right?” Bruce touched his chin. “This just feels weird.”

Tony pointed at him with his fork. “If you shave my face while you’re in there, I will goddamn end you.”

“Play nice, you two,” Natasha said. Her voice was a monotone, but her eyes were sparkling.

Steve gave her an arch look, which was somewhat diminished by the fact that his face was still red. “You started this.”

Natasha just blinked at him. “I have no idea what you’re talking about.”

* * *

After dinner, the team dispersed. Bruce didn’t see where any of the others went (although his educated guess began with “training” and ended with “room”), but he was only focusing on one of them. He’d debated bringing this up at all, but it had been nagging in the back of his mind ever since they’d switched, and the conversation at dinner, lighthearted though it was, had only brought it more to the forefront. 

And so Bruce pulled Tony aside once the room was empty, leading them both out into the hall. Tony gave him a quizzical look, but he didn’t call attention to it or say a word until they were out of the dining room, for which Bruce was extremely grateful. 

The two of them stood in silence for a few moments as Bruce worked out how he wanted to phrase it. Finally, he settled on, “I feel like I should be apologizing.”

“What?” Tony straightened up, and Bruce was reminded of their conversation back on the helicarrier, when they’d first met. When he’d talked about how he didn’t get a suit of armor—Tony had had the same expression that he was wearing now. 

And even months later, Bruce couldn’t comprehend it. 

“This—” Tony made a vague motion in the air “—wasn’t anyone’s fault, strangely enough. Except maybe we could’ve been a little more careful with the alien tech, but if you insist, I can get on board with blaming Thor—”

“No, I mean—” Maybe Bruce shouldn’t have brought this up. “I mean about this.” He gestured to himself before he remembered and gestured at Tony. “That. I know it’s not the most ideal situation for you—I mean,  _ I _ wish I wasn’t myself even when we’re not all mixed up like this.” He tried for a smile, because the way Tony’s face had tightened made him feel like he was saying something wrong. He wasn’t sure what it was; everything he’d said had been common sense. Who  _ would _ want to be stuck inside Bruce Banner’s body, especially when that came with… well, bonus features? 

Bruce was shaken out of his train of thought when Tony reached out and gripped his shoulder, forcing him to look over at eyes that were more hazel than brown-black. 

“Hey,” Tony said. “This situation is… yeah, it’s messed up, there’s no other way to say it; I was trying, but there isn’t. It’s messed up and we’re going to fix it, because I don’t leave problems unfixed, and something tells me that’s not your style either.”

“It is, actually. Kind of by definition.”

“Well, not this time.” 

And they’d all thought  _ Steve _ would be the earnestly determined one of the bunch. 

Tony continued. “‘Cause, you know, there’s already that whole ‘two heads are better than one’ thing. So if we’ve got two heads, but one head is actually the other head, and that head is really the first head, and both heads get to share heads with the other heads—”

“Please,” Bruce said. “Stop talking.”

Tony kept talking. “—then it can only be  _ even _ better, right?”

Bruce smiled in spite of himself. “Or twice as worse.”

“Thaaaat’s the spirit, Banner. You’re stuck with me either way, by the way, I’m just pointing that out. No matter whose bodies we’re in.”

“You have no idea how disturbing that just sounded, do you?”

“Hey, you wanna talk disturbing? Let’s talk about how you pretended to be me well enough to convince  _ Fury _ about it.  _ Nick whatever-that-J-stands-for Fury. _ ” Tony paused. “It’s probably John, right? I feel like that’s popular. Or James or Joseph or something. Not important. Point is, that was impressive. Especially for a guy who can’t lie at card games to save his life.” He shot Bruce a crooked grin. 

Bruce shook his head. “Don’t read too much into it; we spend like eighty percent of our time together.”

Tony frowned. “What’s the other twenty percent?”

“Sleeping. Which, incidentally, I would like to do now, because maybe when I wake up this will all be over.”

“Doubt it, with our luck.” Tony stretched, yawning behind his hand before he spoke again. “Okay, I am  _ beat _ . Is it always like this for you?”

“You mean after a mission? Yeah, pretty much.” He was kind of impressed Tony had maintained his usual high-energy self the entire evening, actually. After a mission that intense, while being the Hulk for hours plural, Bruce in his own body might not have bothered even going to dinner, let alone carrying half of the conversation and teasing Steve every other sentence. 

Although, with the lingering aches and bruises and exhaustion that Bruce could feel from Tony’s body—the kind of things that had to happen with every mission, didn’t they? Every flight in the Iron Man suit where skin knocked against metal, and yet Tony never acted like anything was wrong—he wondered if maybe that was because Tony was used to it. 

Bruce started to walk toward the stairs, Tony following close behind. “Not everybody gets to be Iron Man, Tony,” he finally said, because Tony still had that  _ look  _ on his face, and really, wasn’t it a bit hypocritical of him to be worried about Bruce?

“You do!” Tony grinned as the two of them reached the top of the stairs, each turning in a different direction to head to their rooms. “Good night.”

“Night.”

* * *

Bruce woke up the next morning in his own bed, but still in Tony’s body, which was not the best start to the day. He was wearing the same clothes he’d worn (well, that  _ Tony _ had worn) yesterday, the discomfort of invading his teammate’s privacy stronger than any desire to change. 

He wondered if Tony had changed. 

_ And… yeah, that’s not gonna leave me alone for the rest of the day.  _

Bruce spent a full minute looking for his glasses before he remembered, knocked his elbow into a lamp trying to get dressed with his eyes closed, kept his eyes on the ceiling while he used the bathroom (and he wasn’t  _ touching _ the shower), and went downstairs for breakfast.

The sound of voices greeted him as he entered the kitchen: most of the team grouped around the table in various states of trying to be quiet out of courtesy (Steve), not bothering to be quiet out of courtesy (Natasha), half asleep with their fist squished into their cheek (Thor), and mostly focused on their sesame bagel (Clint). All of which stopped the second they spotted Bruce.

“Morning.” He was received with several guilty expressions and hasty mumbles of “morning” in return, but he let them pretend he hadn’t heard them and pulled a mug from one of the cupboards as Natasha skillfully changed the subject.

Bruce leaned against the counter as the conversation circled around various mundane things: the weather, Natasha’s and Clint’s upcoming missions, an anecdote from Thor about something on Asgard full of words that Bruce couldn’t pronounce if he tried, Steve’s Twitter account. Bruce wasn’t awake enough yet to contribute, so he simply listened and sipped his coffee—which was ever-so-slightly off due to the new set of taste buds, but the difference was minimal enough to ignore.

Eventually, Tony wandered in to join them, having already obtained a cup of coffee from somewhere and either not noticing or not caring that his hair was messed up enough that it looked like he’d been on the receiving end of one of Thor’s staticky high fives. He ignored Steve’s “Morning, Tony,” and beelined for a spot at the counter two feet away from where Bruce was standing. 

If he’d wanted to check whether there had been any changes since last night, Bruce could’ve saved him the trouble: they were still both firmly each other. 

From this close, Bruce had a clear view of the dark circles under Tony’s eyes. He frowned, but before he could say anything, Tony’s gaze had latched onto him.

“Stop wearing those.”

Bruce reflexively looked down at himself. “My clothes?”

“Yes. Stop.” Tony was doing an admirable job keeping a straight face, but it wavered as he reached out to pick at a thread on Bruce’s sweater. “My body was not made to wear sweaters.”

A smile poked at Bruce’s mouth, and he shoved Tony’s hand away. “I’m cold and they’re comfy.” 

“Then ask JARVIS to turn up the heat.” Tony had completely given up on any attempt to hide his grin now. The two of them were standing almost shoulder to shoulder, and Bruce was struck by the ease with which he could now make eye contact. He and Tony were right around the same height normally, but Bruce tended to hunch in on himself while Tony held himself to take up as much space as he could. Now that the situation was reversed, their nervous habits evened out and brought them to the same level. “Come on, I’m a billionaire, I have standards.”

“Says the man who wears Crocs with a dress shirt.”

For once, Tony didn’t retort, leaning back against the counter and taking a drink from his mug. A moment passed, and the kitchen full of superheroes was blissfully silent. Sunlight streamed in through the windows and cast patterns along the wall, because curtains were for people who didn’t want to be constantly reminded of their penthouse view of New York City.

And then Steve spoke. “So.” It was impressive how serious Captain America was able to look while spreading whipped cream over a plate of waffles. “I didn’t want to have to bring this up—”

Clint immediately stood up, pushing his chair back with a screech and turning in the direction of the doorway before Natasha reached over and pushed him back down. 

Steve’s eyes narrowed marginally, but he continued talking as though nothing had happened. “I didn’t want to have to bring this up, but if this…” He circled his fork in the air in the direction of Bruce and Tony “... situation is going to be an issue for a while, I feel like we should maybe discuss some precautions.”

Tony was too far in Bruce’s peripheral vision for him to see his expression, but he could hear the thunk of Tony’s already-empty coffee mug hitting the counter as Tony straightened up.

“Calm down, I’m not suggesting anything drastic,” Steve said. “I’m just saying—if you guys switched bodies, there’s a third passenger in there somewhere.”

Bruce set down his own mug and took a half step forward so that he was standing slightly in front of Tony. “We can handle this, Steve.”

The look on Natasha’s face was entirely too perceptive, and he didn’t like it. 

“It took you years to control the Hulk, Bruce,” Steve pressed. “And you’re…  _ you _ , what the hell makes you think Tony is going to be able to—”

“Yeah, exactly; I’m me, with all my anger issues and—”

“Tony has  _ PTSD and anxiety attacks _ , Bruce.”

At least Steve had stopped calling it shell-shock. 

“Hey,” Tony spoke up from his position against the counter. Bruce was honestly surprised it had taken him this long to interrupt. “Just a reminder that I’m standing right here. In case anybody forgot about that.”

“How could we possibly,” Natasha said under her breath. She was the only one who didn’t look actively uncomfortable by this conversation—Thor had become very interested in the nutrition label on the back of the orange juice container and Clint still looked like he was plotting escape routes. 

And Bruce understood Steve’s point. Possibly more than Steve did himself. But more than that, he knew Tony Stark, and he knew that whatever precautions Steve had in mind were more likely to have the exact opposite effect, particularly when the Hulk was thrown into the mix. 

Besides, hopefully they would be able to swap back soon enough, and this whole discussion would be unnecessary. 

(He had to keep holding on to that thought; it was the only thing that stopped him from having a heart attack every time he accidentally looked into a reflective surface)

(Having a heart attack in Tony’s body would not be a wise course of action)

(Why did this tower have so many reflective surfaces?)

Bruce looked at Steve, who sighed.

“I swear I’m not saying this just to pick a fight.”

“For the first time in eighty years?” That was Tony again. Before Steve could respond, he was already continuing. “Look. Me and Bruce switched places, what, seventeen hours ago? I haven’t felt anything from the big guy—” he tapped the side of his head as though to illustrate “—although if he did want to come out and play, I personally would not be opposed—what?” He caught sight of Bruce shaking his head and changed course. “Or if we didn’t want to do that, which, okay, valid—JARVIS has already been informed of the current circumstances and will simply shift all of the existing protocols to yours truly.”

Tony allowed a pause before holding up a finger and adding, “Also, I’ve been going to therapy, which I’m willing to bet puts me a step ahead of most of you.”

Bruce shifted in his spot as Natasha shrugged, Clint squinted like he was doing mental math, and Thor looked confused. 

Steve at least had the decency to look vaguely guilty before he answered. “If you’re sure that’s going to be enough.” He paused before being seemingly unable to help himself from adding “And I went one time.”

“Glad that’s settled,” Bruce broke in before anybody else could. He turned to Tony. “Lab?”

Tony glanced briefly at Steve, and Bruce was afraid for a moment that this would turn out to be one of their long arguments, the ones that had Tony pulling out the PowerPoint presentations and Steve making the Captain America speeches, but thankfully Tony gestured to the doorway. “After you.”

“Just stay away from big explosions!” Steve called after them as they left the kitchen.

* * *

Breakfast hadn’t ended on the best of notes, but Natasha had S.H.I.E.L.D. things to do and Steve had some sad motorcycling to do and Thor had mentioned something about a bowling alley and Clint had once again vanished off the face of the earth, so no one was around to notice the multiple crashes, bangs, and curses coming from the lab over the course of the next three hours. 

None of them were from the actual experimenting going on—the first had been when Bruce was digging around for an electron microscope without noticing the very large cardboard box teetering on the shelf above it; the second had been when Tony sat down in one of the swivel chairs, forgetting that he’d taken the bolts out of it a few days ago when, and quote: it had been “too spinny;” and the third had been when Bruce wasn’t paying attention and DUM-E ran over his foot—but the rest of the team tended to jump to conclusions. Especially when highly dubious body-switching magic was involved. 

“So, what’re we looking at?” Tony appeared over Bruce’s shoulder, holding a cotton ball between his thumb and forefinger. Bruce spared a glance away from the microscope lens to eye it warily; Tony’s comment fifteen minutes ago about whether radiation poisoning would transfer over once they did switch back was still in the back of his mind. 

He brushed off that thought and focused on Tony. “Well, the samples seem to match what each of our respective DNA looked like before this happened—this wasn’t just a surface-level phenomenon, but we knew that already—meaning my bloodstream has leftover traces of palladium—” he raised his fist in mock celebration “—and you’ve got a system overloaded with gamma radiation.”

Tony did not look as bothered by that news as he should have. “Cool. As long as I’m not going to grow a third eye or something.”

“Side effects may include your repressed emotions gaining a physical form and causing rampant property damage,” Bruce said dryly.

Tony shrugged. “Not seeing a downside.”

Bruce shook his head and bent back over the microscope as Tony continued to think out loud.

“I do feel warmer, though. Like, temperature-wise. Is that part of it?”

Tony was leaning very close now, his shoulder almost right up against Bruce’s back as he apparently tried to peer through Bruce’s head and into the microscope to see the samples for himself. Bruce was very aware that if he were to back up, even just the smallest amount, they would practically be standing in the same spot. His face heated in a way that had nothing to do with the radiation. 

“Yeah,” was all he said. Somehow, Tony did not take this as a cue to move back and instead shifted around so that he was facing Bruce’s other side.

“You are a fascinating person, you know that?” Tony’s voice was musing, but Bruce had spent enough time around him to know that most of his offhand comments were actually the product of five to six business days of overthinking. 

Bruce rubbed his eye where he’d accidentally jabbed himself with the eyepiece. “If you really think so, we can save ourselves a lot of work here.” 

“Fine, I get it. I’ve interrupted a genius at work.” Tony rolled his hand. “Do go on.”

“Thank you.” Bruce took a step back from the microscope and gestured to its contents as Tony leaned forward to look. “Like I said, whatever that piece of Asgardian tech did transferred us completely into each other’s bodies—which raises so many more questions and possibly confirms the existence of a distinct soul? But could also just be the way our brain patterns imprint and the impact of memories and experiences and this needs so much further study, but anyway: it transferred us down to a chromosomal level. The only measurable differences I can find between your body—” Bruce gestured to himself “—the way it was the day before yesterday and the way it is now—same with my body then and now—are some slight abnormalities in the outer layers of the phosphate groups. We should probably do an agarose gel electrophoresis to narrow down the exact components.”

Tony hadn’t taken his eyes off of Bruce for the entire time he’d been speaking. He was still engrossed in the microscope by the time Bruce was done, and so it was probably automatic when he replied with “Oh yeah, talk dirty to me.”

Probably.

Bruce didn’t respond, and it took a second before Tony’s brain apparently caught up with his mouth. Bruce expected the usual smirking, the joking-around, the everything that came with the territory of spending any amount of time with Tony Stark. They’d probably had this exact interaction before, only with less sleep and more hours spent on a rapid-particle-dispersing generator that still blew up every other time they tried to use it. 

This time, though, Tony looked… embarrassed.

And if that didn’t throw Bruce for even more of a loop than the whole switching-bodies thing did.

This was  _ Tony _ . He was never embarrassed, almost by definition. He hadn’t even blinked an eye the time turbulence on the quinjet had resulted in some accidental spooning of Thor, or the time a spontaneous fire in the lab had resulted in an oilcloth over his groin until Bruce had found him some new clothes, or the time some magazine editors had thrown darts at a board and decided to run some kind of celebrity biography thing a few months back. Anyone who didn’t get embarrassed by their own baby pictures was really setting the standard deviation. And yeah, this was Tony, who’d dealt with having every aspect of his life in the public view since before he could talk, but there had to be a line somewhere, right? 

Bruce had personally seen Tony flirt with just about every member of the team at one point or another. So what was different now that it was Bruce?

Because something was different. That was undeniable. 

_ Yeah, maybe because he’s never been talking to someone walking around inside his body before _ , Bruce reminded himself as the two of them went back to work. The only Avenger who could honestly say they’d had that experience was Steve, with all the times Loki had transformed into him before Thor had taken him back to Asgard (None of them would ever look at the first floor bathroom at Avengers Tower the same way again and they would just have to deal with that), but Bruce wasn’t about to go asking him for advice. Captain America had been successfully repressing his emotions since the Great Depression, he was not the person to go to with I-switched-bodies-with-my-best-friend-and-now-I’m-afraid-that’s-going-to-affect-our-professional-relationship problems. 

It didn’t matter, though. As soon as they figured out how to get both of them back in the right bodies, they could put this whole thing behind them. 

And the solution to that was somewhere in this little microscope slide.

* * *

Bruce didn’t know how much time had passed, but his eyes hurt from straining at data and the numbers on the holographic screens lit up around him were starting to become a light blue blur by the time he finally looked up.

He wasn’t sure at first, what had caught his attention enough to draw it away from the still-scrolling blocks of text on the screens, but after a few moments of utter silence, he heard it again.

The noise.

Soft and small and barely perceptible, but still there and still familiar enough that it had Bruce dropping his tablet and hurrying across the room without bothering to switch off the simulation he had going.

It didn’t take long to locate Tony; a few hours into the experiments, it had become obvious that Tony’s lack of sleep the night before—along with the residual exhaustion from the battle and Bruce’s body’s transformation—was affecting the quality of work, not to mention his ability to remain upright, and he had passed out on the couch with a halfhearted mutter of “wake me up in five minutes.” Once he was asleep, however, he was out cold, all the tension on his face settling as his limbs relaxed, and after he’d sleepily curled himself around a cushion… yeah, there was no way Bruce was waking him up. So he’d let Tony sleep, sprawled out like a starfish with the soft sounds of his breathing providing a background for Bruce’s work, and the hours had silently ticked by. 

Now, though… maybe letting Tony sleep for so long hadn’t been as good an idea as Bruce had thought.

Bruce jumped the last step down into the lower level of the lab, and both the couch and its occupant came into a fuller view. Tony had tucked his arms in close to his body, in stark contrast from the usual way he stretched to take up the most possible space, and his face was twisted up even as his eyes were still tightly shut. He was twitching, too, jerking in his sleep, and the muffled sounds that came out of his mouth were exactly what had caught Bruce’s attention.

Bruce knelt down beside the couch, his hand hovering over Tony’s shoulder for a moment before he decided to risk it and laid it down, giving a gentle shake. “Tony. Hey, Tony, come on, it’s okay.”

Tony twitched again, giving no sign that he had even heard. Bruce could feel the muscles in Tony’s shoulder tensing under his grip as Tony muttered something else under his breath. He seemed right on the edge of consciousness, but wouldn’t be getting there himself.

“ _ Tony. _ ”

Bruce’s hand was flung off as Tony shot into a sitting position with a gasp, rubbing a hand across his face like he had a bad taste in his mouth. Bruce couldn’t shake the feeling that there was still something wrong, there was something very wrong, and he didn’t move from his position on the floor.

When Tony’s eyes flew open, they were glowing gamma green.

Bruce didn’t think he could’ve stood up any faster.

“What’s going on?” Tony’s voice was still thick with sleep that hadn’t quite worn off, but his hands were clenched tight on the arm of the couch and his eyes were wide, making their color undeniable. “What is this?” He squeezed his eyes shut like he had a headache before opening them again, the green bright and vivid.

“Okay.” Bruce wasn’t positive he was actually speaking aloud until Tony’s head swiveled around to look at him. “You have to calm down. It’ll be fine, just breathe and—”

“Bruce?” And now Tony sounded scared, actually scared, and there were tiny lines of green veins starting to peek out at the spot where the collar of his T-shirt met his neck. Signs that Bruce had seen a hundred times before, but never like this, never from the outside, and  _ how was he supposed to do this— _

“Tony, just breathe. Panicking will make it harder, you just have to calm down.” Bruce cut himself off when he noticed his voice start to waver, because he could not afford to be freaking out himself right now; Tony needed him and he had to stay measured and calm and— “It’ll be okay.”

Tony’s breathing was already speeding up. “I—I can feel him.”

“I know. Don’t think about that, just focus on something else, focus on me, okay?”

But Bruce had already lost him. He could tell, the moment his words started to fade out of Tony’s hearing as the sound of his own pumping heart rushed over it all and drowned everything else out. As Tony’s hands gripped the armrest of the couch hard enough to dent as his limbs began to bulge and the green flush spread further over his skin. As his face was twisting, all familiarity shoved away, and never during any time in the past twenty-four hours had Tony Stark looked so much like Bruce Banner.

_ Maybe Steve did have a point. _

Bruce stared frantically around the lab, but JARVIS’s procedures for a Hulk appearance (which mainly consisted of lockdowns. Very, very secure lockdowns) only activated once any other people were out of the room. They’d debated about this, but ultimately decided that no one wanted to be locked in with an angry Hulk—but that protocol was meant for people who were actually planning to  _ escape _ , and there was no way Bruce was leaving Tony right now. 

He couldn’t count on reinforcements, either, because none of the other Avengers would voluntarily touch the lab with a ten-foot—

And then Natasha was there, moving from the doorway to the couch in what felt like the space of a single heartbeat, and it was only after Tony’s eyes rolled back and he dropped to the ground did Bruce notice the miniature syringe in her hand. 

He wasn’t paying much attention to that, however, because his eyes were fixed on Tony’s collapsed form on the floor. As he watched, the places where the fabric of Tony’s clothes had been straining settled back down, and veins faded and sunk back into pale skin. 

Natasha was saying something. Bruce blinked and looked up at her. “Sorry, what?”

“I said the tranquilizer shouldn’t last long. It’s one of the trial versions S.H.I.E.L.D. was developing for you.” Natasha’s voice was as calm as ever as she discussed this, her gaze on Tony. Her hair was in a messy ponytail and she was wearing a jacket that had about a ninety percent chance of belonging to Clint over loose workout clothes, and Bruce wondered what she had been doing before she came up here. “Good thing I knew where Tony kept it.”

“I guess so. Thanks,” Bruce added, belatedly. 

Natasha shrugged. “I’ve had a lot of practice jabbing syringes into Tony’s neck.” Her gaze traveled up from the floor to land on Bruce, and a frown appeared on her face. “Hey, you okay?”

It took a moment for the words to filter into Bruce’s brain, and another before he had enough control to nod. He couldn’t get the image out of his head: a sight that he was not supposed to be seeing, not as a bystander instead of a passenger—the act of watching all control fail and vulnerability expose itself, and it wasn’t supposed to get this far, Tony wasn’t supposed to  _ need  _ to—

“No, you’re not.” Natasha continued to watch him.

“And how are you so sure?” 

Natasha sighed. “Because I know what Tony looks like when he’s having a panic attack.”

“Okay, maybe I’m a little freaked out,” Bruce admitted. He stumbled back into a table, his hands reaching up to press against his face, and the harsh lights of the lab faded to a dim reddish glow through his eyelids. Natasha didn’t say anything else, and he was grateful, because this was just embarrassing, wasn’t it, and this was the reason there had even been a need to develop that stupid tranquilizer, and he really needed to get ahold of himself. 

Breath in. Breath out.

Fortunately, being in Tony’s body had the advantage of  _ not _ having a rage-filled alter ego straining at the surface every time his heart rate jumped even a little bit. 

It was incredible how much easier it was to calm down without that. 

Breath in. Breath out.

Bruce opened his eyes. Natasha was still standing there. He shouldn’t have been surprised. 

Almost in unison, the two of them glanced down at Tony’s unconscious form on the floor. The green had almost completely receded from his skin, and he now looked to be sleeping peacefully—albeit in an interesting choice of location.

Natasha turned to Bruce. “I’ll take his legs?”

* * *

Tony woke up sometime after dinner that night. Bruce knew this, because he was in the lab when Tony came back down, after spending the rest of the day definitely  _ not _ hiding and refusing any offers from the team to talk or eat or train or “just do something other than look at cells and shit, Bruce, it’s not gonna kill you.” That last one had been Clint, and Bruce had just stared at him until he left. 

Now, Tony swung himself around to the other side of the lab table, offhandedly tapping a short rhythm on its surface before looking up to meet Bruce’s eyes. Without any preamble, he announced, “So, that was terrifying.”

Bruce had been poring over some of the latest readings, but at that he gave a laugh that was more out of relief than anything else. “Do you get it now? Why I try so hard?”

“Maybe a little better.” Tony gave a shudder and slid over to join Bruce at the bench. If he moved a hairsbreadth to his left, their shoulders could be touching. “However, I would like to make it clear that I am still a dedicated advocate for the Give Big Green a Chance club.”

Bruce shook his head. “Sometimes your levels of stubborn and danger-addicted never cease to amaze me.”

“C’mon, the big guy just needs a hug.” Tony grinned, but his eyes were serious. “He was scared. You  _ have _ to feel it if I did.”

“Of course I feel it, but the problem is that when you’re scared and nine feet tall and a thousand pounds of muscle, stuff tends to get wrecked.” Bruce ignored the little catch in his voice as he added, much quieter: “Sometimes, it’s not just stuff.”

Tony slid closer, decreasing the distance between them to about zero, and Bruce forgot how to breathe. “Eight.”

“What?” The fabric of their sleeves seemed sheer-thin as their arms brushed together—

“Eight feet tall. Not nine. I get the point you’re trying to make, but come on, Banner, you can’t fudge on me.”

Inexplicably, Bruce felt himself smile. “Does it really make a difference?”

“Yes. Yes, it does. Just like this extra inch makes a difference.” Tony held out his hand parallel to the top of his head, measuring it against Bruce’s. They were sitting close enough that Bruce could feel the whoosh of air against his hair as Tony waved his hand back and forth between them.

“If that’s the worst part about being in my body, I wouldn’t be complaining.”

“I don’t think you understand just how attached I am to that inch, green bean.”

Bruce opened a new window on one of the screens and started to transfer the latest round of data. “I’ll keep that in context for you.”

Tony let out a delighted laugh. “You’re so mean to me.”

Without thinking about it, Bruce gave Tony’s shoulder a little nudge, and steadily ignored the resulting sparks as the two of them went back to work.

* * *

It was about half an hour later when Bruce looked up from his calculations to see Tony swearing and rubbing his eye. There was a microscope in front of him, and from the way Tony was glaring at it, Bruce could make a pretty good guess as to what had happened.

When he noticed Bruce watching him, Tony slid off Bruce’s glasses and held them up. “This is why I don’t wear these.”

Bruce typed another set of numbers into the holoscreen before answering. “Well… okay, I wasn’t going to say anything, but—”

“Don’t even.”

“—but I kind of think you need them.”

“Sacrilege. Lies and slander.”

“It’s not a death sentence, you know.” Bruce gestured vaguely to the opposite wall. “I just noticed that some things are a little blurry from far a—”

He was interrupted by Tony pulling open a nearby drawer, picking out an object, and placing it in Bruce’s hands.

“These are sunglasses, Tony.”

“They’re prescription.” Tony shrugged. “I wear ‘em to—”

Bruce grinned. “To maintain your ego?”

“Wow. Harsh.” Tony held up a finger. “Not unfounded, but harsh.” He watched as Bruce slipped on the sunglasses and blinked.

“Huh.” Bruce took the sunglasses off again and turned them over in his hands. “These actually—wait a second, are you telling me Iron Man flies his suit without being able to see?”

“‘Course not.” Tony managed to look marginally offended, which was something, at least. “There’s lenses. And I have the HUD. And JARVIS.”

“Well, that’s a relief.” Bruce continued turning the sunglasses over before setting them down on the table. “And must have been fun for Rhodey the first time he flew War Machine.”

Tony snorted. “First of all, Rhodey’s been making fun of me and my refusal to get contacts since college. And second, those were just bonus features; I didn’t add them to the War Machine suit.”

Bruce frowned. Granted, the accounts from his other teammates about what they had been doing before New York had blurred together a bit (there was no way Clint and Thor had  _ known _ each other), but he was pretty sure the creation of War Machine hadn’t been deliberate. From the way Natasha had told it, anyway. “I thought the story was that Rhodey stole it during your birthday party.” 

“That is the story, yes.”

“It’s not true?”

“Of course it’s not true, come on, you really think anyone can steal an Iron Man suit without my express permission? Because people have tried, you know. A vast assortment of people. And governments. And questionable relatives.” Tony paused, and silence hung in the balance before he abruptly continued with, “I wanted it to be Rhodey, you know. At first. After, uh, Afghanistan. I wanted it to be him in the suit. He’s got the experience, brains, common sense—”

“Not sure common sense is a prerequisite for owning an Iron Man suit,” Bruce mused.

Tony clapped a hand over his chest. Bruce noticed that—even though Tony was in Bruce’s body, which had never held an arc reactor and would have no reason to hurt in that area—he was still careful to avoid the place directly above his heart. “I am baring my soul here, you’re not supposed to be insulting me.”

“I’m sorry, go on.”

Tony let out a breath, and his gaze drifted off to somewhere in the corner before snapping back to Bruce. “I wanted it to be Rhodey. But I knew I had to do it… it was all my fault, all of that…” Tony waved his hand. “That. Stark Industries, the weapons, the Ten Rings. My fault. My problem,” he added, and his eyes flickered with faint surprise when Bruce shook his head. “I couldn’t just stand back and watch while other people fixed it, even my best friend.”

“But you did make him a suit.” It felt like the room was full of threads, each pulling in a different direction. Tony’s eyes were wide behind the pair of Bruce’s glasses he was still wearing, his movements slightly stiffer from the tranquilizer, and Bruce thought that more than anything, he looked like… 

“I did.” Tony shrugged again. “Like I said, I wanted it to be him.”

_ But this was all happening at the same time as the palladium and— _

All of Bruce’s thoughts seemed to grind to a halt. “Tony…”

Tony very studiously did not look at him. “What? It was the logical thing to—”

It was because Tony was not looking at him that Tony did not see when Bruce stood up and stepped forward, and continued not to see until his arms were full of gamma physicist.

“Bruce, what—”

The rest of Tony’s reply was essentially cut off as Bruce tightened his arms around him, and a moment later Bruce felt the hug being returned. They stood like that for a moment, wrapped around each other while also  _ being _ each other, which was a unique experience in itself, but made so much more so by the fact that this was Tony, and this was Bruce, and it didn’t matter who was in whose body when they were standing in the same place.

Bruce finally spoke, and his words were muffled by the fabric of Tony’s shirt. “I’m glad you’re Iron Man.”

He could feel the vibrations of Tony’s laugh. “Didn’t peg you for a hugger, big guy.”

“Yeah, well…” Bruce wondered if this was a cue to stop, but all thoughts of that were quickly dispelled as Tony somehow managed to pull him even closer. “Special circumstances.”

“Are you saying I can only hug you when you’re in my body?”

“Ew, no, that’s creepy. And—” Bruce tilted his head slightly, and Tony mirrored the movement so that their eyes met. It was in the eyes, the way to really tell them apart despite the body they were in, because this was a look that only Tony Stark could give, and whatever words Bruce had been about to say evaporated from his mouth.

It wasn’t such a huge step, the kiss.

Neither was the second one.

The third one—okay, that was where things started to get more complicated, but once you considered the previous data, it wasn’t too hard to extrapolate to the next conclusion—

Bruce stopped counting after that.

Eventually, he pulled away, and Tony made a noise, but Bruce only glanced around the lab—at the night-dark windows, wide-open doors, and sweeping staircase leading to the rest of the penthouse—and murmured, “Okay, maybe not  _ here _ .”

“Brucie,” Tony murmured back instantly, and Bruce tried not to dissolve on the spot at the nickname. “As long as you keep doing  _ that _ , I couldn’t care less where we go.” 

And he meant it, too—he let Bruce drag him all the way to his bedroom (Bruce’s bedroom; the beds were all the same size anyway and there was a greatly reduced risk of visitors lurking in the ceiling vents), where the concept of “standing up” hardly survived two seconds before both of them were on the bed, the weights of weeks finally lifted off their shoulders. 

Bruce couldn’t remember ever feeling so warm—and in the dark, it was impossible to tell who was who.

* * *

The next morning, when Bruce woke up, he was tangled in the sheets next to a fast-asleep Tony.

A fast-asleep  _ Tony _ .

Actually Tony this time, with his messed-up hair and his crooked smile that rested on his face as he cuddled a pillow and his goatee that he’d threatened Bruce not to shave. Tony, back in his body, the way it was supposed to be—and when Bruce looked down at himself, he saw that the same had happened to him. For better or for worse.

Bruce breathed a slow sigh of relief, and that was when the alarm clock went off.

Bruce leaned across the bed to hit the button, but Tony was already shifting and blinking awake, his expression morphing from annoyed to confused to surprised to a sleepy grin that set off a chain reaction inside Bruce’s brain.

“Hey,” Tony said, stretching so that he was propped up by his elbow on the pillow. “I guess Hammer Time had a point after all.”

“Mm-hm.” Bruce laid back down, his gaze still roving over Tony’s face, taking in every detail. Had he always had that little scar at the edge of his hairline? And his eyelashes were so long… 

Tony seemed to notice the particular angle that Bruce’s head was tilted at and grinned. “So… now that we’ve got that weirdness out of the way… round two?” He slid his arm out from under the blankets to drift behind Bruce’s shoulders, tracing the outline with a familiar hand.

Bruce smiled, letting himself sink into the embrace. “Maybe shower first.”

**Author's Note:**

> Thanks for reading!


End file.
